The over-all objective of this research is to study the functional properties of selected abnormal human hemoglobins by measuring their oxygen binding equilibria under various conditions of pH, salt concentrations, temperatures, and in the presence and absence of certain organic phosphates. The results will be used in attempts to explain the presence or lack of clinical abnormalities such as erythrocytosis or anemia associated with specific abnormal hemoglobins and to extend our knowledge and understanding of the contribution of specific amino acid residues in hemoglobin to its oxygen transport function. The studies are divided into two levels of investigation. The first consists of screening new or previously unstudied mutant hemoglobins for general parameters of O2 binding including P50, Hill's "n" coefficient of cooperativity, Bohr effect, influence of organic phosphates and Cl- effect. The second level of investigation is to measure the O2-Hb equilibrium curve as completely as possible for mutants with altered function. The results are being analyzed in terms of the Adair equation in an attempt to identify which steps in the oxygenation of hemoglobin are most altered in the mutational change in structure.